I know the question looks similar but I did not find any answer to my problem, hence posting it here. Thanks in advance for any help.
I had Ubuntu 14.04 installed alongside Windows 8.1 and both showing up in boot sequence (with UEFI - 'Enabled', Fast Boot 'Disabled' and Secure boot - 'Disabled').
However, to run a web application (not supported in Ubuntu 14.04), I installed Ubuntu 12.04. Installation was done by enabling 'Legacy Support' and 'Legacy First' in BIOS.
After installation, I can see all three (12.04, 14.04 and Win 8.1) in the boot menu when 'Legacy Support' is enabled in BIOS. However, only 12.04 and 14.04 works. If I try the Windows option, I get an error.
If I turn on 'UEFI' in BIOS, I can boot 14.04 & Win 8.1 successfully. However, 12.04 is not showing up even in the generic options (12.04 is Ubuntu 13.03.74 or something - Sorry, cannot remember the exact nomenclature).
Tried boot-repair (both ways - installed in Ubuntu and as a start up USB). When run from terminal, it gives an error and asks me to run in USB as a start-up disk. When run in USB, the disk is ignored with USB boot Enabled in both modes (UEFI as well as Legacy).